1. Field of the Invention
This invention relates to a shade device for a transparent roof element, a window or the like, especially for motor vehicles, comprising a winding shaft with a fabric shade which can be wound onto or off of it, a draw bar which can moved in the winding and unwinding direction of the shade and which is located on the free end of the fabric shade, a draw cable arrangement which acts in the pull-out direction and which engages the draw bar, and a reset spring which is assigned to the winding shaft and which is tensioned when the shade is pulled out.
2. Description of Related Art
These shade devices are, for example, as a sunshade for a motor vehicle roof with a transparent or translucent cover which is assigned to the roof opening, as a glare shield in motor vehicle rear windows, as a vision shield in side motor vehicle windows, or the like. A general requirement for these shade devices, in addition to ease of handling and high operating reliability, is simple structure and a small space requirement. This applies especially to shade devices on motor vehicle roofs for which only a extremely small installation space is available.
Shade systems of the initially described type are characterized in that a drive force need only be applied in one direction, specifically the pull-out or closing direction, while the take-up or opening motion is effected by the reset spring which is tensioned during closing. This enables a simple, space-saving structure of the shade system and the assigned drive devices.
Another problem has also always been the exact parallel guidance of the draw bar which ensures jam-free motion of this draw bar and fold-free opening and closing of the shade. For this purpose, generally, a draw cable engages each end of the bar, and it must be ensured that the two draw cables are uniformly retracted during the closing motion and let out during the opening motion.
The aforementioned problems, especially the problem of the space requirement for the shade device, are exacerbated when there are to be two or more shade devices which are arranged in succession, as can be the case, for example, in very long vehicles, such as busses.
Published German Patent Application DE 197 32 686 A1 discloses an arrangement in which the draw cable arrangement has a single draw cable which runs from a fixed point located in the closing direction in front of the draw bar, via a first deflection roller which is located in the area of the first bar end, then via a second deflection roller located in the area of the second bar end, and from there to a drawing mechanism which pulls out the shade and which is located in front of the draw bar in the closing direction.
The draw cable accordingly has one fixed end which can be regarded as held at the fixed point, and one loose end which is connected directly, or optionally via deflectors, to the drawing mechanism. The draw cable can be not only cables, but can be any type of flexible drawing means, such as chains, belts, cables, bands or the like. The deflection rollers are preferably pivotally supported rollers; however, in a simpler embodiment and for jam-free guidance of the draw bar, there can also be stationary rollers, bolts or pins in place of deflection rollers, or there can be a guide channel for the draw cable on the draw bar.
When a tensile force is applied to the loose cable end and the entire cable length between the fixed point and the drawing mechanism is shortened, this shortening is distributed uniformly on the cable section which is assigned to the fixed point and to the cable section which is assigned to the point of application of the drawing force so that the draw bar is moved parallel to itself in the closing direction. In a corresponding manner the unwound cable length is distributed uniformly on the cable section assigned to the fixed point and the cable section assigned to the point of application of the drawing force when the draw cable is let out at the point of application of the drawing force, so that the draw bar moves under the action of the reset spring which drives the winding shaft uniformly in the opening direction.
In this way, with a cable adjustment mechanism which acts on a single draw cable, uniform and correct opening and closing of the shade device can be effected. It goes without saying that the deflection rollers should move easily and the cable should be guided without friction as much as possible via these deflection rollers.
The above described shade device has only been implemented to date in simple shades, since construction in arrangements with two or more shades is an obstacle to implementation and especially the problem of the space requirement for the drive devices of several shades is difficult to solve, especially in motor vehicles.
German Patent DE 42 13 108 C2 discloses a shade device with three shades which are located behind one another. However, the shades are connected directly to one another, i.e., they behave like a single shade, which increasingly clears a single area, for example, when opening and which covers the opening again when closing.
German Patent DE 197 50 713 C1 discloses a shade device with two fabric shades which can be wound onto a common winding shaft. Such a device allows only one closing or opening direction of the two shades at a time so that, in this respect, it can only be used to a limited degree; moreover, it is limited to two shades, i.e., more than two shades cannot be coupled to one another using this principle.
The object of the invention is to devise a shade device in which the entire surface which is to be covered by shades can be distributed among two or more individual shades with simple structural means and with a space requirement as small as possible.
This object is achieved in accordance with the present invention by:
at least two identical shades being provided,
all shades being actuatable at the same time by the same drawing mechanism,
the draw cables of the shades being attached at one end to separate, shade-specific fixed points and at their other end being wound onto separate, shade-specific drum sections which are located next to one another on a drive shaft of the drawing mechanism, and
the winding diameters (b1, b2) of the shade-specific drum sections being matched to the pull-out lengths of the shades such that all shades can be moved at the same time into their open and closed position by the drive shaft of the drawing mechanism.
First of all, the entire surface to be covered is efficiently divided and distributed among several shades, i.e., next to the first shade, there are at least one and optionally also several shades.
To simplify construction, all shades can be actuated at the same time by the same drawing mechanism, i.e., the cable ends of all shades are connected to a single drawing mechanism. To do this, these cable ends can each be wound onto separate, shade-specific drum sections which are located next to one another on the same drive shaft of the drawing mechanism; in order to take into account optionally different pull-out lengths of the shades, the winding diameters of the drum sections are each matched to the assigned pull-out lengths so that all the shades reach their pulled-out or taken-up position at the same time.
Other favorable embodiments of the individual shades and the assigned components of their drive systems are described below.
The winding diameters are easily determined such that the numerical ratio of respective shade pull-out lengths is equal to the numerical ratio of the winding diameter of the associated drum sections.
In order to further improve the run-off of the draw cable via the deflection rollers without slippage, and thus jam-free adjustment of the draw bar, according to one embodiment, it is provided that the two deflection rollers are rotationally coupled to one another and are thus synchronized.
In order to keep the required cable force as small as possible, it is provided that, preferably, both the cable section which is guided to the fixed point and also the cable section which is guided to the drawing mechanism each run essentially in the plane of the shade and in the closing direction, i.e., perpendicular to the draw bar so that there are no components of the cable force which are inactive for the closing motion.
The fixed point can be a point, for example, in which the cable is held in a cable clamping device. However, in order to be more free in terms of construction, the fixed point can also be defined, for example, by a cable deflection device via which the draw cable is guided to a cable clamping device located to the rear. It is irrelevant for the operation of the shade device that the draw cable runs behind the cable deflection device, but this expands the possibilities for an arrangement of the cable clamping device in structurally favorable terms.
Similarly, the drawing mechanism can directly, or optionally via deflectors, engage the assigned cable section. The latter embodiment, in turn, enables a structurally, largely free arrangement of the drawing mechanism, as is explained in detail below.
Especially in horizontal shade devices, i.e., for example, in shade devices for a motor vehicle roof, it is effective and conventional to guide the draw bar in guide rails which are arranged lateral with respect to the closing direction; in this case, according to another embodiment of the invention, it is provided that the cable sections guided to the fixed point and to the drawing mechanism each run in an assigned guide rail. In this way, these cable sections, on the one hand, themselves, acquire guidance, and on the other hand, they are covered in an aesthetically pleasing manner by the guide rails.
An aesthetically pleasing approach which is likewise structurally favorable arises according to another embodiment of the invention in that the reset spring is a flat spiral spring which is located within the winding shaft, with one spring end which is connected to the rotary winding shaft and with the other end connected to a torsionally strong bearing journal or the like which projects into the winding shaft.
The cable adjustment mechanism, in the simplest case, can be a handle which is located on the loose end of the cable, via which a drawing force can be applied to the draw cable, and which, for example, can be suspended in a suitable locking device for locking the shade device. However, in one preferred embodiment, the cable adjustment mechanism comprises cable drums which, in the simplest case, can be rotationally-driven manually, but preferably are driven by means of an electric motor.
Several embodiment of the invention are shown in the drawings and are explained in detail with reference thereto below.